>>118412386>>118412414The main culprit in the 1990s-2006 was Mike Carlin, who was head of the Superman office and later Executive Editor of the entire company (Didio eventually replaced him).
Carlin gained a lot of power from running the four Superman books, and Death and Return was great in sales.
He hated the JSA because all he wanted to do was sell new characters in new books. His hatred led to the Justice Society of America ongoing book in 1992 being cancelled prematurely and never collected*
The biggest move he made was changing Jurgens' plan for the JSA in Zero Hour. Jurgens wanted to remake Earth-2 after that event, but Carlin rejected it and ordered him to kill off most members of the JSA. So some, like Doctor Fate, died and were replaced by that FATE book instead.
The funny upside is that the Robinson Starman book was successful, and that, combined with the Vertigo Sandman Dodds book led to the JSA ongoing revival in 1998.
Under Didio there were eventually three JSA books that ran at the same time, but when the New 52 happened he declared them a "retired concept" and launched the young-and-hip Earth-2 disaster.
*lots of DC stuff is never collected, but specifically the miniseries and the later ongoing have been solicited many times, only to mysteriously get cancelled out of the blue. There is currently a HC announced for the mini, and we have to wait and see if it comes out